1. Field of the Invention
The present invention generally relates to a memory module, and in particular to a RAM bus module.
2. The Prior Art
As capabilities of a computer become significantly enhanced, memory capacity for the computer increases. Memory modules, such as a dual in-line memory module (DIMM) comprising a circuit board with a number of memory chips mounted thereon, are commonly employed in a personal computer. The DIMM device is usually connected to a main computer board by means of a card edge connector. The card edge connector forms a slot which receives an edge of a circuit board of the DIMM. Contacts are arranged in the slot for electrically engaging with conductive traces of the DIMM circuit board thereby forming electrical connection therebetween.
As speed and capacity of the DIMM device increase, protecting the DIMM device from external electromagnetic interference and properly removing heat from the memory chips thereof become serious issues to be addressed. It is thus desired to have a memory module which eliminates these problems.
Accordingly, an object of the present invention is to provide a memory module protected from external electromagnetic interference by a shielding member.
Another object of the present invention is to provide a memory module capable of removing heat generated by memory chips thereof during operation.
To achieve the above objects, a memory module in accordance with the present invention comprises a circuit board on which memory chips are mounted and a metal casing attached to the circuit board for shielding the memory chips. Conductive traces are formed on the circuit board for electrically engaging corresponding portions of the casing to ground the casing. The casing forms a raised portion defining a space for accommodating the memory chips. A recess is formed on the raised portion and a bottom surface thereof contacts the memory chip to conduct and remove heat from the memory chips. Ventilation holes are defined in the raised portion for facilitating heat removal. The casing forms two positioning pins inserted into corresponding positioning holes defined in the circuit board for properly positioning the casing with respect to the circuit board. The casing also forms two latching arms engaging corresponding latching holes defined in the circuit board for securing the casing to the circuit board.